Theft control apparatus for trays



Dec. 6, 1966 N. NORMAN THEFT CONTROL APPARATUS FOR TRAYS 5 Sheets-Sheet 1 Filed Sept. 20, 1965 INVENTOR. NATHAN NORMA/V BY @449 ATTORNEYS Dec. 6, 1966 N. NORMAN 3,289,443

THEFT CONTROL APPARATUS FOR mus Filed Sept. 20, 1965 s SheetsSheet 2 I IN V EN TOR. /\/4 THAN No/www A T TO/PA/E V5 Dec. 6, 1966 N. NORMAN 3,

THEFT CONTROL APPARATUS FOR TRAYS Filed Sept. 20, 1965 5 Sheets-Sheet 5 INVENTOR. MTHAA/ A/ORMfl/V BY @ww United States Patent 3,289,443 THEFT CONTRQL APPARATUS FOR TRAYS Nathan Norman, Toledo, Ohio, assignor to Eprad Incorporated, Toledo, Ohio, a corporation of Ohio Filed Sept. 20, 1965, Ser. No. 492,983 16 Claims. (Cl. 7tl-276) This application is a continuation-in-part application of my co-pending application, Serial No. 315,117, filed October 3, 1963, now abandoned, which, in turn, is a continuation-in-part of my co-pending application, Serial No. 299,293, filed August 1, 1963, and now abandoned.

This invention relates to theft control apparatus for trays and more particularly to such apparatus for looking a food tray on a support at a drive-in-restaurant or the like.

In earlier years, food trays used at drive-in restaurants commonly had an attached bracket to enable the tray to be hung directly on an automobile door. The special brackets and trays had several disadvantages, including being more expensive than conventional trays as well as being heavier and harder to handle. Such trays also periodically were accidentally knocked off the automobile door and also had another important disadvantage in that when the customer desired to leave, he could not do so until the waitress was summoned and removed the tray. This was often time consuming, particularly during the rush periods.

Drive-in restaurants are now more commonly equipped with posts each located between two parking stations or spaces, intended for customer automobiles with each post carrying a menu sign displaying the bill-of-fare. The post not only supports the menu sign but also often is equipped with a communication system so that the customer can transmit his order directly to the kitchen after reading the menu. The post additionally serves an important function in carrying a tray support for each customers automobile with the tray support being swingable so that the support and a tray placed thereon can be moved toward and away from the customers automobile door. In this manner, the tray can be moved toward and away from the automobile at the convenience of the customer so that he can get into and out of the automobile and drive away without interference from the food tray This arrangement has several advantages over the older system in which the food tray was hung directly on the customers automobile. For one thing, conventional food trays can be used in connection with the swingable tray supports, which trays are much less expensive, are lighter in weight, and can be more easily handled by the waitress. Also, the driver can leave the premises whenever finished without the necessity of waiting for the waitress to remove the tray.

Drive-in restaurants have long been plagued with the loss of food trays. This has been particularly true for larger drive-in restaurants with spaces or stations for customers automobiles at remote locations from the kitchen headquarters, making it less obvious for the occupant of an automobile to depart with a tray. Tray losses also tend to be particularly heavy when a drive-in restaurant opens in a new locality and neighborhood customers do not yet have a large supply of their own trays. In many instances, it is not uncommon for busy drive-in restau rants to have food tray losses amounting to $100-$200 per month.

The present invention relates to theft control apparatus for food trays to prevent substantially all unauthorized removal of the trays from the tray supports and enable the apparatus to pay for itself in a relatively short period of time. The theft control apparatus can be attached to existing equipment already installed at drive-in restaurants as well as incorporated into newly manufactured equipment. The theft control apparatus includes locking means for holding the tray in position on the tray support and in the preferred form, the locking means is magnetically operated with no key at all being required. By embodying a magnetic locking means, and eliminating the need for a key, the drive-in customer usually is not even aware of the fact that the food tray is locked on the support unless, of course, he attempts to remove it. Not being aware of the fact that the tray is locked on the support, the customer is then not insulted as he may otherwise be if the waitress uses a key obviously to prevent removal of the tray by the customer. Further, without a key, the locking operation of the tray on the support is reduced to a minimum amount of time, with time being of the essence in rush periods at drive-in restaurants. In one embodiment, the magnetic locking device automatically locks the tray when it is moved into position. In removing the empty tray, the locking device is positioned so that the waitress can release it even though she is carrying an additional tray in one hand, thereby not impairing her efficiency since she can still use both hands.

It is, therefore, a principal object of the invention to provide theft control apparatus for food trays employed at drive-in restaurants and the like.

Another object of the invention is to provide theft control apparatus for food trays, which apparatus has the advantages outlined above.

Other objects and advantges of the invention will be apparent from the following detailed description of preferred embodiments thereof, reference being made to the accompanying drawings, in which:

FIG. 1 is a somewhat schematic view in perspective of a supporting post, menu sign, and swingable tray support as commonly found at drive-in restaurants;

FIG. 2 is an enlarged view in perspective of a food tray and a tray support embodying the invention;

FIG. 3 is a fragmentary view in perspective of a food tray embodying the invention;

FIG. 4 is a fragmentary view in cross section of a food tray stop shown in FIG. 2;

FIG. 5 is a fragmentary view in cross section taken through a lock housing of the apparatus of FIG. 2;

FIG. 6 is a view in perspective of a magnetic device used to release the tray from the housing of FIGS. 2 and 5;

FIG. 7 is an enlarged view in perspective of a food tray and a tray support incorporating a slightly modified embodiment of the invention;

FIG. 8 is a view in vertical cross section taken along the line 88 of FIG. 7;

FIG. 9 is a view in vertical cross secction taken along the line 99 of FIG. 7;

FIG. 10 is a fragmentary view in perspective of another modified embodiment of the invention;

FIG. 11 is a view in perspective of a food tray and a tray support incorporating a modified embodiment of the invention;

FIG. 12 is an enlarged view in perspective of a portion of the apparatus shown in FIG. 11;

FIG. 13 is a view in cross section taken along the line 13-13 of FIG. 12; and

FIG. 14 is a view in cross section taken along the line 14-14 of FIG. 12.

Referring to the drawings and more particularly to FIG. 1, a typical supporting post as used between two parking spaces or stations for customers automobiles is indicated at 10. Supported on the post 10 is a menu sign 12 having a menu on each side for the occupants of adjacent automobiles. When the drive-in restaurant incorporates a communication system, the post 10 can also hold a speaker (not shown) by means of which the customer, can transmit his order directly to the kitchen, which saves one trip for the waitress. The post also carries a tray support 14 for each automobile station which support is movable with respect to the post 10 by means of a jointed tray support arm 16. The arm 16 enables the tray support 14 to be moved in all directions toward and away from the door of the customers automobile. With this arrangement, the tray support can be adjusted for various positions of the automobile and the support can also be moved toward and away from the automobile door so that the customer can easily alight or enter it, if desired, without interference with the tray. Further, when the customer is ready to leave, he can simply push the tray support 14 away from the automobile and depart.

A more or less conventional food tray 18 can be used with the support 14 without the additional bracket which is required when the tray is to be hung on the automobile door. As previously discussed, the tray 18 without the bracket is less expensive, lighter, and easier to handle.

With the tray supports and trays heretofore known it was possible for a customer to pick up the tray from the support and leave with it. This was particularly easy at larger drive-in restaurants where the automobiles and trays were remote from the kitchen headquarters, particularly at night. To overcome this problem, theft control apparatus as shown more particularly in FIGS. 2-6 is employed with the tray support 14 and the tray 18. As shown, the apparatus actually comprises several components which are designed specifically to be attached to existing tray supports and existing trays. It is to be understood however that the apparatus can be incorporated in new trays and supports. The theft control apparatus includes a pair of end stops 20 for the food tray 18 which are designed to be attached to an edge of the food tray support 14 toward the swingable arm 16. When the food tray support 14 is made of metal such as aluminum, the tray stops 20 can be attached to the support by self-threading screws 22 (FIG. 4) after appropriate holes are drilled in the edge of the support 14. The tray stops 20 have lower tabs 24 which are designed to lie adjacent the lower surface of the tray support 14 so as to steady the stop 20, thereby providing a secure attachment with the use of only one of the screws 22. The tray stop 20 also includes an upper tab 26 which extends over the end of the tray 18 to prevent the tray from being lifted, even though it is not positioned with its end snugly against stop 20. Two additional tray stops 28 are attached to an adjacent edge of the tray support 14 with the stops 28 being similar in design to the stops 20 and attached by similar means. However, upper tabs 30 of the'tray stops 28 are shorter than the upper tabs 26 of the tray stops 20. The tray stops 20 and 28 are not absolutely essential but do serve to prevent a customer from maliciously picking up an edge of the tray 18 and breaking it loose from the support 14, as will be apparent subsequently.

A lock housing 32 can be affixed to the tray support 14 by means of a single nut and bolt 34 and is located by the longitudinal edge of the tray 18 opposite the longitudinal edge adjacent the tray stops 28. The lock housing 32 is made of non-magnetic material and has in an end wall thereof, a notch 36 which receives a latching tab 38 aflixed to the tray 18. Within the housing 32 is a latching member 40 having an arm 42 pivotally mounted in the housing by a pivot pin 44 and a hook portion 46 designed to cooperate with the tray tab 38. At least a portion of the latch member 40 is made of magnetic material so that it can be raised by a magnet, as will be discussed more fully.

A flange 48 (FIG. 3) is bent upwardly from the tray latching tab 38 to enable the tab to be attached to a sidewall of the food tray 18 by means of two small nuts and bolts indicated at 50, or by similar fasteners. The flange 48 and the fasteners enable the tab 38 to be supported by the tray support 14 through the tray 18 when on the support and constitute, in combination, means for preventing removal of the tray when engaged by a latch member. The tab 38 has an opening 52 therein which is designed to receive the hook portion 46 of the latch 40 when the tray 18 is positioned on the support 14. The opening 52 can extend completely through the tab 38 or can be in the form of a recess or notch, in either case being an opening in the upper surface of the tab.

When the tray 18 is moved onto the support 14 with an end of the tray moved under the upper tabs 26 of the tray stops 20, the one longitudinal edge of the tray will also slide under the upper tabs 30 of the tray stops 28. At this time, the tray tab 38 moves into the slot 36 of the housing 32 and cams or forces the latch 40 upwardly. This is made possible by the fact that the lower end of the hook portion 46 is sloped or curved and also by the fact that the tab 38 is tapered, as shown in FIG. 3. The tray 16 is moved into position until the hook portion 46 drops into the opening 52, at which time the end of the tray may or may not be in contact with the stops 20 but, in any event, the end of the tray is under the upper tabs 26. By making the tabs 26 long enough, usually longer than the tabs 30, the lock housing 32 can have a reasonable tolerance as to its position on the support 14 and still operate satisfactorily. Some tolerance can also be achieved as to the transverse position of the lock housing 32 with respect to the stops 28 by making the tab 38 and the slot or recess 52 therein of a width substantially greater than the thickness of the latch member 40. While the hook portion 46 of the latch member 40 can be de signed to drop over the entire tab 38, by employing the opening 52 the hook portion 46 cannot be lifted above the tab 38 by one slipping a knife blade through the slot 36 in the housing 32, for example. This result is achieved because the rear or thicker portion of the tab 38 shields; the hook portion 46 of the member 40.

Referring more particularly to FIG. 6, a magnet 54 is carried by a wrist band 56 for the purpose of releasing; the tray 18. To achieve this, the magnet 54 is placed on top of the lock housing 32 with the magnet 54- then attracting the latch member 40 which is of magnetic material. The latch member 40 is thereby raised to the top of the housing 32 and separated from the tab 38, enabling: the waitress to grasp the tray 18 and slide it free of the tray stops 20 and 28 and the housing 32. The magnet; 54 and the wrist band 56 preferably are positioned on thewaitress hand in a manner such that the magnet 54 is on the back of the forearm. In this position, the waitresscan simply place the back of her forearm on the housing: 32 with her palm up, to effect the release. The released. tray is then grasped and removed with her other hand. In this manner, the waitress can have another empty tray in the hand which she uses to effect the release, preferably the right hand in the present instance, so that her efficiency is not impaired whatsoever by the theft control apparatus- The magnet 54 preferably is disguised so that its nature will not be readily apparent to the customers. For this purpose, the magnet 54 can be built into a pocket of the; band 56, as shown, or can be covered with fabric which will not impair the strength of the magnet. As another modification, the magnet can be shorter or of circular shape and mounted in a case similar to that of a watch so as to appear to be a Wristwatch. Of course, if the waitresses Wear long sleeves, the magnet 54 will be hidden thereby and no covering is required. If desired, the strap 56 can carry two magnets, one on top and one on the bottom so that the tray can be released with the palm of the hand either down or up.

It will be seen from the above description that the instant invention has many advantages. The four tray stops 20 and 28 can be easily attached to an existing tray support simply by drilling four holes in the edges thereof and inserting the screws 22 which can be self-tapping if the tray support 14 is of metal. The lock housing 32 can then be positioned and fastened by the nut and bolt 34 which extends through the support 14 and is fastened from the bottom. The tab 38 also is easily mounted on the tray simply by the use of the two small nuts and bolts 50 fastened to the upper tab portion 48. The theft control apparatus is then completely installed in a short period of time.

With the invention, the tray 18 can be simply slid into position with respect to the stops 20 and 28 and latched in place without the use of any auxiliary device so that essentially no extra time is required in placing a tray on the support 14. In removing the tray 18, the magnet on the back of the waitress forearm is simply placed on the housing 32 to raise the latch member 40, thereby enabling the waitress to slide the tray out with her other hand. As pointed out, the palm of the hand can be up during this operation so that the waitress can be holding another tray or any other object during the releasing operation to enable both hands to be useful. Thus, the releasing operation only requires a minute period of time to be accomplished without impairing the efficiency of the Waitress.

If the housing 32, latch member 40, and tray tab 38 are strong enough, the tray stops 20 and 28 need not be used since they primarily prevent a customer from twisting a tray loose although they also help guide the tray tab 38 into the slot 36. Also, the latch member 40 can be mounted for pivotal movement in a horizontal plane with a spring used to urge the member to the locking position. In such an instance, the tray tab can be in the form of a barb which is pushed into the lock housing.

FIGS. 7-9 show a slightly modified embodiment of the invention in which the latching tab is not attached to the tray so that the food trays do not have to be modified in any manner. The trays thus do not have and projections which might interfere when they are being washed or otherwise handled nor do the trays have to be specially oriented when they are placed on the tray supports.

A tray support 58 is somewhat similar to the tray support 14 except that the tray support 58 has a side plate 60 for the lock housing. The tray support 58 also has three tray stops 62, one of which is located at the end of a tray 64 while the other two are located at opposite sides of the tray 64. The tray stops 62 prevent longitudinal movement of the tray in one direction and also prevent any transverse movement of the tray.

A lock housing 66 can be bolted to the supporting plate 60 and is made of any suitable non-magnetic material, as before. A latching member 68 is pivotally supported in the housing 66 and includes a hook portion 70 to cooperate with a latching tab. At least a portion of the latch member 68 is of magnetic material so that it can be raised by a magnet in the same manner as the latch member 40.

To prevent the tray 64 from being removed from the tray support 58 in the other longitudinal direction, a pivotable tray stop 72 is located at the edge of the support 58 opposite the end tray stop 62. The tray stop 72 is affixed to a pivot rod or shaft 74 by small screws 76 or the like and the rod 74 is pivotally supported below the tray support 58 by bearing members 78. The bearing members 78 in this instance are in the form of eyebolts with self-tapping threads which can be screwed into the bottom of the support 58 after pilot holes are drilled therein. Of course, many other types of connecting means can be used for the bearing members 78. A latching tab 80 is afiixed, as by brazing, to the pivot rod 74 in a position such that it can be inserted in an end opening 82 in the lock housing 66. The latching tab 80 has an opening 84 in an end portion thereof to receive the hook portion 70 of the locking member 68 when the pivotable tray stop 72 is in its upper position. In this position, the tray stop 72 prevents removal of the tray 64 and the tray stop 72 cannot be moved out of the way 6 because the pivot rod 74 to which it is attached is held in a fixed position by means of the latching tab 80.

In operation, when the waitress places the tray 64 on the support'58 with three of the tray edges under the tray stops 62, she swings upwardly the tray stop 72 until the latching tab moves into the end opening 82 and the hook portion 70 moves into the tab opening 84. When it is desired to remove the tray 64, the magnet 54 of FIG. 6 is placed on top of the non-magnetic housing 66 to cause the locking member 68 to move upwardly and free the latching tab 80. Because of the off-center position of the tray stop 72, it will swing downwardly to an out-of-the-way position, along with the latching tab 80, as soon as the lock member 68 is raised. The waitress then simply removes the tray. The unlocking and removing operation again can be accomplished with one hand and arm, if desired.

While the operation of the theft control apparatus will be observed and figured out by an occasional customer, even then few trays will be removed from the premises. First of all, magnets strong enough to operate the latch members 40 and 68 are not readily available and are not likely to be purchased only for the purpose of removing a tray or two from a drive-in restaurant. Second, even if a customer has a magnet available, he is not often likely to remember to bring it when he goes out for food. In addition, many who would otherwise leave with a tray would think twice about doing so 'by the mere fact that it is latched in position, rendering the act of taking it more serious to many people. Consequently, when the theft control apparatus is employed, losses of trays will be drastically reduced even though not completely eliminated.

FIG. 10 shows a slightly modified locking arrangement for the tray 64 on the tray support 58. In this instance, a pivotable tray stop and a latching tab are combined. A modified lock housing 84 is mounted on the supporting plate 60 and includes a pivot pin 86 which pivotally supports a pivotable tray stop 88, a portion of which extends through a slot 90 in the housing. The stop 88 has an integral latching tab 92 elocated within the housing 84, which tab is effective to prevent removal of the tray 64 when in position on the support 58. A modified locking member 94 is pivotally supported in a vertical plane in the housing 84 by a pin 96 and can be operated with any suitable magnet, as before. In this instance, the locking member 94 has a hook portion 98 slanted in the opposite direction to the previous hook portion 78 because the tab 92 which it engages moves in the opposite direction.

In operation, when the tray 64 is placed on the support, the pivotable stop 88 is swung into position behind it to prevent removal thereof. At the same time, the tab 92 swings under the hook portion 98 of the lock member 94 and moves it upwardly, until it drops down behind the tab 92 to prevent movement of the tab in the opposite direction. This prevents movement of the stop 88 and locks the tray in position. When the tray is to be released, the magnet is used on the housing 84 to raise the hook 98 and to enable the waitress to slide the tray 64 outwardly at the same time pivoting back the stop 88 in a counterclockwise direction and moving the tab 92 back beyond the hook portion 98. If desired, of course, the locking member 94 could be used to engage the stop 88 at an intermediate portion between its outer end and the pivot pin 86, in which instance this portion would constitute the locking tab. The hook portion 98 would then have a slanted end similar to that of FIG. 9.

FIGS. 1114 show another slightly modified embodiment of the invention with a locking arrangement similar to that of FIG. 10. Referring to FIG. 11, a tray support 100 can be of conventional design, similar to the support 14 of FIG. 1. In this instance, however, rather than affixing the various individual tray stops 62 of FIG. 7 or 20 and 28 of FIG. 2 to the support 100, a separate tray holder 102 is employed. The tray holder 102 has integral side tabs or stops 104 and 106 and an integral end tab 108 bent up from a main plate 110 which can be affixed to the tray support 100 by bolts or rivets extending through fastener openings 112. The tray holder 102 also has a side plate 114 suitably affixed thereto for holding a lock housing 116. With this arrangement, the entire assembly of the tabs 104, 106, and 108 and the lock housing 116 can be assembled to an existing tray support by means of a few fasteners. Since the tabs and the 'lock housing are all fixed relative to the plate 110,

.proper spacing and cooperation between the various components are assured.

It has been found that the tray holder 102 has utility even without the lock housing 116 since the retaining tabs are effective to prevent a tray from being dropped from the support 100 due to accidental bumping or to wind, for example.

The lock housing 116 is suitably mounted on the side plate 114 by rivets or bolts and includes a notch or slot 118 for a pivotable tray stop 120. The tray stop 120 is pivotally attached to the side plate 114 by a pivot pin or rivet 122. The tray stop 120 has an integral latching tab 124 located within the housing 116, similar to the construction of FIG. 10. The tray stop 120 also has a vertical extension 126 extending above the food tray to enable a waitress to release the stop 120 with her fingers when the magnet on her wrist is placed on the housing 116. This assures that the waitress can unlock, release, and remove the tray with one hand, should the other one be full.

With the latching member 40, 68, or 94, the food trays sometimes can be released by bouncing the tray support. Thus, a teen-agar, for example, can bang on the tray support 14 or 58 and cause the latching member to bounce sufilciently high that it will clear the tab with which it is associated, thereby enabling the tray to be released. However, it has been found that this problem can be eliminated by balancing the latching member, as shown particularly in FIG. 13.

Accordingly, a balanced latching member 128 has a slanted hook portion 130 located in the path of the tab 124 and is designed to be pushed down further by the tab when engaged thereby to further assure a locking effect. The latching member 128 can be of any suitable design, as long as it remains balanced and out of contact with the side plate 114 when supported freely. To further assure clearance between the hook portion 130 of the latching members 128 and the plate 114, a suitable indentation or dimple 132 is formed in the plate 114 under the hook portion 130. As shown, the latching member 128 is freely supported on a pivot 134 affixed to an ear 136 which, in turn, is suitably attached by rivets or spot welding to the side plate 114. Both the pivot 134 and the supporting ear 136 preferably are made of nonmagnetic material. With the balanced latching member, it will not move clear of the path of the tab 124 no matter how hard the support tray 100 is bounced.

In some instances, a customer occasionally will bring a magnet with him to the drive-in restaurant and release a tray. It has also been found that such magnets usually are stronger than those carried by the waitresses. To overcome this problem, a blocking member 138 of FIG. 14 is used. The blocking member 138 has a blocking projection 140 carried at one end thereof and has a central portion pivotally connected to a wall of the latch housing 116, in this instance by a suitable non-magnetic pivot 142. If an excessively strong magnet is employed, not only will the latching member 128 be raised but the blocking member 138 also will be raised to place the locking projection 140 in the path of the tab. Hence, while the strong magnet will release the locking member 128, it will lift into operation the blocking member 138. Unlike the latching member 128, the blocking member 138 need not necessarily be balanced.

While the blocking member 138 prevents an excessively strong magnet from operating the tray release, a weak magnet could ordinarily operate the latching member 128 since it is balanced and only a light force is required to operate it. However, by locating the latching member and particularly the end portions thereof well below the top of the lock housing 116, a stronger magnet is required. In the event that space considerations prevent a sufficient distance between the latching member 128 and the top of the housing, only a central part of the latching member 128, near the pivot 134, need be made of magnetic material so that the effect of the magnetic force will produce a smaller torque tending to move the latching member. Hence, between the design of the latching member 128 and the addition of the blocking member 138, a very specific magnetic force must be employed to effect a release of the tray.

The latching member and the blocking member preferably are designed so that release of the tray can be effected only if a magnet having a strength within twentyfive percent of a predetermined magnitude is used. For a weaker magnet, the latching member will not be released, and for a stronger magnet, the blocking member will be moved. One magnet which has been found to be particularly effective is a ceramic magnet available from Indiana General Magnetic Corporation of Valparaiso, Indiana. This magnet loses only nineteen percent of its strength over a period of seven years.

The concept of using two or more of the latching or blocking members in its broadest form provides a unique locking device for preventing separation of any two relatively movable members. By properly designing and positioning the latching or blocking members, they can release the relative movable members only Within a very narrow range of field strengths. Further, a plurality of combinations of latching and blocking members can be used, with each operable by a separate magnet having a predetermined strength lying in a narrow range. A lock requiring several magnets is thus possible which is as sensitive as a combination lock, and which is pickproof.

Rather than using a magnet to attract and lift the locking member, the member can carry a magnet, and a second magnet with a pole of similar polarity can be employed outside the housing to repel the first magnet and raise the locking member. This can be accomplished by using the external magnet underneath the housing or above the housing at a point on the side of the pivot pin opposite the hook, to repel that portion of the locking member and to raise the hook.

Numerous modifications of the above described embodiment of the invention will be apparent to those skilled in the art, and it is to be clearly understood that such modifications can be made without departing from the scope of the invention, if they are within the spirit and the tenor of the accompanying claims.

I claim:

1. For a food tray support of the type used in drive-in restaurants and a food tray to be supported thereon, means for locking the food tray on the support comprising a pair of first stop means adapted to be attached to an edge of said support at spaced positions therealong, said first stop means having upper tabs adapted to extend over an end portion of the food tray to prevent upward movement thereof, first fastening means for removably attaching said first stop means to the edge of said support, a lock housing, second fastening means for attaching said lock housing to said tray support at a predetermined position spaced from said first stop means, a latch member, means for pivotally mounting said latch member in said housing for pivotal movement in a generally vertical plane, said latch member being of a magnetic material and adapted to be raised when subjected to a magnetic field, said latch member having a hook portion extending downwardly therefrom with the end of said hook portion sloping, second stop means adapted to be attached to an edge of said tray support and spaced from said lock housing a distance approximately equal to the width of the food tray to prevent horizontal movement of the tray in a direction away from said lock housing, third fastening means for attaching said second stop means to the edge of said tray support, a tab adapted to be attached to said food tray and to extend beyond said food tray and into said lock housing when said tray is positioned on said support, said tab having an opening therein to receive the hook portion of said latch member, said tab tapering in thickness throughout its width with the thinner edge of said tab being positioned to contact said end of said hook portion when said tray is moved into position, thereby to raise said latch member until said hook portion is received in said opening of said tab, a magnet for raising said latch member when placed on top of said housing, and a wrist band attached to said magnet and adapted to be worn on a wrist of a waitress, whereby the waitress can place the magnet on top of the housing and remove the tray with the other hand.

2. For a food tray support of the type used in drive-in restaurants and a food tray to be supported thereon, means for locking the food tray on the support comprising means for said support to limit movement of said tray, means for attaching said first means to said support, a lock housing for said tray support to be located at a predetermined position spaced from said first means, a latch member, means for pivotally mounting said latch member in said housing for pivotal movement in a generally vertical plane, at least a portion of said latch member being of a magnetic material and adapted to be raised when subjected to a magnetic field, said latch member having a hook portion extending downwardly therefrom, and means including a tab supportable on the food tray and adapted to extend into said lock housing when said tray is positioned on said support and being effective to prevent removal of the tray from said support, said tab being adapted to engage the hook portion of said latch member, an edge of said tab being adapted to contact said hook portion when said tray is moved into position, and to raise said latch member until said hook portion is engaged in locking relationship with said tab.

3. For a food tray support of the type used in drive-in restaurants and a food tray to be supported thereon, means for locking the food tray on the support comprising means for said support to limit movement of said tray in all but one direction, means for attaching said first means to said support, a lock housing for said tray support to be located at a predetermined position spaced from said first means, a latch member, means for pivotally mounting said latch member in said housing for pivotal movement in a generally vertical plane, at least a portion of said latch member being of a magnetic material and adapted to be raised when subjected to a magnetic field, said latch member having a hook portion extending downwardly therefrom, means cooperating with said hook portion when in a lower position and positioned to be engageable with said tray to prevent movement of said tray if moved in said one direction, a magnet for raising said latch member to clear said preventing means when placed against said housing, and a wrist band attached to said magnet and adapted to be worn on a wrist of a waitress, whereby the waitress can place the magnet on top of the housing and remove the tray with the other hand.

4. For a food tray support of the type used in drive-in restaurants and a food tray to be supported thereon, means for locking the food tray on the support comprising means for said support to limit movement of said tray, a lock housing for said tray support to be located in a predetermined position spaced from said first means, a latch member, means for movably mounting said latch member in said housing for movement between an engage position and a release position, at least a portion of said latch member being of a magnetic material and adapted to be moved from the engage position to the release position when subjected to a magnetic field, said latch member having a hook portion extending therefrom, means including a tab movably supported relative to said lock housing and adapted to extend into said lock housing when said tray is positioned on said support and effective to prevent removal of the tray from said support, said tab being adapted to contact said hook portion when said tray is moved into position, and to raise said latch member until said hook portion is engaged with said tab, a magnet for raising said latch member when placed on top of said housing, and means attached to said magnet to enable it to be worn by a Waitress, whereby the waitress can place the magnet against the housing and release the tray.

5. For a food tray support of the type used in drive-in restaurants and a food tray to be supported thereon, means for locking the food tray on the support comprising a magnetically releasable latch member, means for movably mounting said latch member relative to said support for movement between an engage position and a release position, and means including a tab movably supported by the food tray support when said tray is on said support and adapted to be engaged by said latch member.

6. A food tray support of the type used in drive-in restaurants having means for locking the food tray on the support comprising a latch member, means for movably mounting said latch member relative to said support for movement between a first position and a release position, means including a tab movably supported by the food tray support when said tray is on said support and adapted to be engaged by said latch member to prevent removal of the tray from said support, a magnet effective to cause said latch member to move from said first position to said release position to enable said tab to be moved and a tray to be removed from said support, and a band attached to said magnet and adapted to be worn by a waitress, whereby the waitress can release the tray.

7. For a food tray support of the type used in drivein restaurants and a food tray to be supported thereon, means for locking the food tray on the support comprising a latch member, means for movably mounting said latch member on said support for movement between a first position and a release position, tab means movably supported by said food tray support at least when said tray is on said support to prevent removal of the tray when in a predetermined position on said support and engaged by said latch member, and means adapted to be carried by a waitress to cause said latch member to move from said first position to said release positionto clear said tab means and enable the tray to be removed.

8. For a food tray support of the type used in drivein restaurants and a food tray to be supported thereon, means for locking the food tray on the support comprising a lock housing for said tray support to be located in a predetermined position, a latch member, means for movably mounting said latch member in said housing for movement between an engage position and a release position, at least a portion of said latch member being of a magnetic material and adapted to be moved from the engage position to the release position, and a tab adapted to engage said member when said tray is positioned on said support, said tab being effective to prevent removal of the tray from said support.

9. For a food tray support of the type used in a drivein restaurant and a food tray to be supported thereby, means for locking the food tray on the support comprising means for positioning the tray on the support in a generally predetermined position, and magnetically releasable locking means for preventing removal of the food tray from the support until said locking means is released, said releasable locking means including means engageable with the food tray to limit movement thereof, and magnetically-responsive means having one position engageable with said engageable means to prevent removal of the tray and a second position spaced from said engageable means when subjected to a magnetic field to enable movement of said engageable means and removal of the tray.

10. For a food tray support of the type used in drivein restaurants and a food tray to be supported thereon, means for locking the food tray on the support comprising means for said support to limit movement of said tray in at least one direction, a latch member, means for movably mounting said latch member relative to said support for movement between an engage position and a release position, said latch member being adapted to be selectively moved by a waitress from the engage position to the release position, a movable tray stop to be movably connected to said tray support and to move between a first position in which it is out of the way of the tray and a second position in which it prevents movement of the tray in an additional direction, and means functionally integral with said tray stop and adapted to be engaged by said latch member when said tray is moved into position and said stop is moved to its second position, said integral means thereby being effective to prevent movement of said tray stop.

11. Locking means according to claim wherein said integral means is a part of said tray stop.

12. A food tray support of the type used in drive-in restaurants for supporting a food tray thereon, said support having means for locking the food tray on the support comprising means for said support to limit movement of said tray in at least one direction, housing means associated with said support located in a predetermined position with respect to said limiting means, a latch member, means for movably mounting said latch member in said housing means for movement between an engage position and a release position, a movable tray stop movably connected to said tray support to move between a first position in which it is out of the way of the tray and a second position in which it prevents movement of the tray in an additional direction, and means functionally integral with said tray stop and adapted to be engaged by said latch member when said tray is moved into position to prevent movement of said tray stop.

13. For a food tray support of the type used in drivein restaurants and a food tray to be supported thereon, means for locking the food tray on the support comprising a lock housing for said tray support to be located in a predetermined position, a balanced latch member, means for movably mounting said latch member in said housing for movement between an engage position and a release position, said balanced member bearing said tray support in both positions, at least a portion of said latch member being of a magnetic material and adapted to be moved from the engage position to the release position when subjected to a magnetic field, and a tab adapted to extend into said lock housing when said tray is positioned on said support and effective to prevent removal of the tray from said support when said latch member is in the engage position.

14. For a food tray support of the type used in drivein restaurants and a food tray to be supported thereon, means for locking the food tray on the support comprising a lock housing for said tray support to be located in a predetermined position, means engageable with the tray, a latch member, means for movably mounting said latch member in said housing for movement between an engage position in which said member is adapted to flock said food tray by preventing movement of said engageable means and a release position in which said member is adapted to be spaced from said food tray, at least a portion of said latch member being of a magnetic material and adapted to be moved from the engage position to the release position when subjected to a magnetic field within a range of predetermined magnitude, and a blocking member in said housing having a clear position and a blocking position, said blocking member moving from the clear position to the blocking position when subject to a magnetic field stronger than the predetermined range.

15. A locking device to prevent separation of two members which are capable of relative movement with respect to one another, said device comprising a latching member connected to the first of said relative movable members and having a portion lying in the path of the second of said members to prevent separation thereof, said latching member being moved out of the path of the second member when subjected to a field exceeding a predetermined strength, a blocking member attached to one of said relative movable members and lying free of a path of the other of said relative movable members, said blocking member being moved into the path of the other relative movable member when subjected to a field of predetermined strength which is in excess of the first predetermined strength, whereby said first and second relative movable members are capable of moving relative to one another only when said latching and said blocking members are subjected to a field exceeding the first strength and less than the second strength.

16. For a food tray support of the type used in a drivein restaurant and a food tray to be supported thereby, means for locking the food tray on the support comprising means for positioning the tray on the support in a generally predetermined position, a movable tray stop supported on said support to prevent removal of said tray when said stop is in one position, and magnetically releasable locking means for preventing movement of said tray stop until said locking means is released.

References Cited by the Examiner UNITED STATES PATENTS 407,477 7/1889 EZell. 2,516,801 7/1950 Renaud 248407 X 3,031,086 4/1962 Blair 2lll33 3,095,723 7/1963 McKnight et al. 69 3,169,743 2/1965 Page 248206 FOREIGN PATENTS 18,859 1899 Great Britain.

BOBBY R. GAY, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,289,443 December 6, 1966 Nathan Norman It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 53, for "secction" read section column 5, line 35, for "and" read any column 7, line 48., for "members" read member column 10, line 22, after "member" strike out the period, and insert to prevent removal of the tray from said support.

Signed and sealed this 19th day of September 1967.

( L) Attest:

ERNEST W. SWIDER EDWARD J. BRENNEI Attesting Officer Commissioner of Patents 

3. FOR A FOOD TRAY SUPPORT OF THE TYPE USED IN DRIVE-IN RESTAURANTS AND A FOOD TRAY TO BE SUPPORTED THEREON, MEANS FOR LOCKING THE FOOD TRAY ON THE SUPPORT COMPRISING MEANS FOR SAID SUPPORT TO LIMIT MOVEMENT OF SAID TRAY IN ALL BUT ONE DIRECTION, MEANS FOR ATTACHING SAID FIRST MEANS TO SAID SUPPORT, A LOCK HOUSING FOR SAID TRAY SUPPORT TO BE LOCATED AT A PREDETERMINED POSITION SPACED FROM SAID FIRST MEANS, A LATCH MEMBER, MEANS FOR PIVOTALLY MOUNTING SAID LATCH MEMBER IN SAID HOUSING FOR PIVOTAL MOVEMENT IN A GENERALLY VERTICAL PLANE, AT LEAST A PORTION OF SAID LATCH MEMBER BEING OF A MAGNETIC MATERIAL AND ADAPTED TO BE RAISED WHEN SUBJECTED TO A MAGNETIC FIELD, SAID LATCH MEMBER HAVING A HOOK PORTION EXTENDING DOWNWARDLY THEREFROM, MEANS COOPERATING WITH SAID HOOK PORTION WHEN IN A LOWER POSITION AND POSITIONED TO BE ENGAGEABLE WITH SAID TARY TO PREVENT MOVEMENT OF SAID TRAY IF MOVED IN SAID ONE DIRECTION, A MAGNET FOR RAISING SAID LATCH MEMBER TO CLEAR SAID PREVENTING MEANS WHEN PLACED AGAINST SAID HOUSING, AND A WRIST BAND ATTACHED TO SAID MAGNET AND ADAPTED TO BE WORN ON A WRIST OF A WAITRESS, WHEREBY THE WAITRESS CAN PLACE THE MAGNET ON TOP OF THE HOUSING AND REMOVE THE TRAY WITH THE OTHER HAND. 